1-D WO3@BiVO4 heterojunctions with highly enhanced photoelectrochemical performance

Abstract

1-Dimentional WO3@ BiVO4 heterojunction thin films are prepared for the first time by combining a flame vapor deposition (FVD) process with spin coating method. A rapid, economical FVD system are developed, which incorporates a controllable wire feeder with precise feed rate for the growth of sub-stoichiometic tungsten oxide nanowires. These flame synthesized WO3 nanowires provide high interfacial contact area for the coating of BiVO4 shells. The WO3@BiVO4 heterojunction nanowire array utilizes the individual strengths of WO3 (good electron transport property) and BiVO4 (strong light absorption) and exhibits superior performance under back illumination. The optimal thickness of WO3 nanowires for best-performing nanostructured WO3@BiVO4 thin film is found in this study. This WO3@BiVO4 photoanode produces a photocurrent of up to 3.8 mA/cm2 under simulated solar light back illumination (100 mW/cm2) at 1.23 V vs. RHE (reversible hydrogen electrode). The present work offers a promising practical route for the preparation of 1-dimentional WO3 based composites photoanode for photoelectrochemical water splitting.